Has the feature confirmed its viability over the time passed?
Some people just mindlessly abuse it, thus an invite spam in notifications. Not all CG coders are happy with being harrassed that way.
I guess it’d be better to have such a prerequisite as “(only if they follow you)” in order to stop the invite spam by unfollowing a spammer or to have some sort of a slider in profile settings to switch off annoying invites completely.
Another way is to filter out the list of online people, i.e. to show only those who’ve paricipated in clashes recently.